use Core Sans font

.github/workflows/ci.yml

@@ -15,6 +15,17 @@ jobs:
       - uses: actions/checkout@v4
         with:
           fetch-depth: 0
+      - uses: actions/checkout@v4
+        with:
+          fetch-depth: 0
+          repository: mainmatter/core-sans-a-fonts
+          ssh-key: ${{ secrets.SSH_PRIVATE_KEY }}
+          path: core-sans-a-fonts
+      - name: Install Fonts
+        run: |
+          sudo cp -r core-sans-a-fonts/* /usr/local/share/fonts/
+          sudo fc-cache -f -v
+          fc-list | grep "Core Sans"
       - uses: actions-rust-lang/setup-rust-toolchain@v1
       - name: Install exercise plugin
         run: cargo install --path helpers/mdbook-exercise-linker